Pressure and shear stress caused by raindrop impact at the soil surface: Scaling laws depending on the water depth

Abstract : Raindrop impact is an important process in soil erosion. Through its pressure and shear stress, raindrop impact causes a significant detachment of the soil material, making this material available for transport by sheet flow. Thanks to the accurate Navier-Stokes equations solver Gerris, we simulate the impact of a single raindrop of diameter D, at terminal velocity, on water layers of different thickness h: D 10 , D 5 , D 3 , D 2 , D, 2D, in order to study pressures and shear stresses involved in raindrop erosion. These complex numerical simulations help to understand precisely the dynamics of the raindrop impact, quantifying in particular the pressure and the shear stress fields. A detailed analysis of these fields is performed and self-similar structures are identified for the pressure and the shear stress on the soil surface. The evolution of these self-similar structures are investigated as the aspect ratio h/D varies. We find that the pressure and the shear stress have a specific dependence on the ratio between the drop diameter and the water layer thickness and that the scaling laws recently proposed in fluid mechanics are also applicable to raindrops, paving the road to obtain effective models of soil erosion by raindrops. In particular , we obtain a scaling law formula for the dependance of the maximum shear stress on the soil on the water depth, quantity that is crucial for quantifying erosion materials.
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Earth Surface Processes and Landforms, Wiley, 2016, 41 (9), pp.1199-1210. <10.1002/esp.3894>
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Contributeur : Carine Lucas <>
Soumis le : lundi 13 février 2017 - 18:20:23
Dernière modification le : jeudi 16 février 2017 - 01:07:23

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Amina Nouhou Bako, Frédéric Darboux, Francois James, Christophe Josserand, Carine Lucas. Pressure and shear stress caused by raindrop impact at the soil surface: Scaling laws depending on the water depth. Earth Surface Processes and Landforms, Wiley, 2016, 41 (9), pp.1199-1210. <10.1002/esp.3894>. <hal-01281209v2>

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